IOTA/IOTA-ES occultation update for (127) Johanna / HIP 75934 event on 2012 Sep 15, 19:51 UT Visible from S Africa Summary ------- On 2012 Sep 15 UT, the 114 km diameter asteroid (127) Johanna will occult a 10.1 mag star in the constellation Libra for observers along a path across S Africa. In the case of an occultation, the combined light of the asteroid and the star will drop by 3.9 mag to 14.0 mag (the magnitude of the asteroid) for at most 3.8 seconds. This update is based on UNSO/Flagstaff astrometry for the asteroid kindly provided by Hugh Harris, TMO astrometry for the asteroid kindly provided by Bill Owen, historical astrometry from the MPC files (via AstDys), and the following catalogs for the star position: UCAC. The event at a glimpse ---------------------- * Rank: 79 * date and approx. time of event: 2012 Sep 15, 19:53 - 2012 Sep 15, 19:55 UT * geocentric midpoint of event [JD]: 2456186.32785833 * magnitude of target star: 10.1 * magnitude drop [mag]: 3.9 * estimated maximum duration [s]: 3.8 * Moon: 0 % sunlit, 66° distance * Sun: 63° distance * rough path description: S Africa The occultation path -------------------- * approximate projected width [km]: 116 * 1 sigma uncertainty interval [path widths]: +/- 0.70 * 1 sigma uncertainty interval [seconds]: +/- 2.1 * 1 sigma uncertainty interval approx RA,DE ["]: (+/- .030 +/- .035) * 1 sigma uncertainty ellipse (major, minor, PA): ( .035", .030", 1° ) * approx speed of asteroid's shadow [km/s]: 30.3370 * website for maps: http://www.asteroidoccultation.com Path Coordinates: Occultation of HIP 75934 by 127 Johanna on 2012 Sep 15 Centre Star Star Sun Path Limits Error Limits E. Longitude Latitude U.T. Alt Az Alt Limit 1 Limit 2 Limit 3 Limit 4 o ' " o ' " h m s o o o o ' " o ' " o ' " o ' " Latitude Latitude Latitude Latitude - 31 0 0 -39 30 24 19 53 40 61 292 -1 -40 1 53 -38 58 58 -40 46 4 -38 15 3 - 30 0 0 -39 30 42 19 53 42 60 291 -1 -40 2 11 -38 59 16 -40 46 21 -38 15 21 - 29 0 0 -39 30 36 19 53 45 59 290 -2 -40 2 5 -38 59 10 -40 46 15 -38 15 15 - 28 0 0 -39 30 6 19 53 47 58 289 -3 -40 1 35 -38 58 40 -40 45 46 -38 14 45 - 27 0 0 -39 29 13 19 53 50 58 288 -4 -40 0 42 -38 57 46 -40 44 54 -38 13 51 - 26 0 0 -39 27 55 19 53 52 57 287 -5 -39 59 26 -38 56 29 -40 43 38 -38 12 33 - 25 0 0 -39 26 15 19 53 54 56 286 -5 -39 57 45 -38 54 47 -40 41 58 -38 10 51 - 24 0 0 -39 24 10 19 53 57 56 285 -6 -39 55 42 -38 52 42 -40 39 56 -38 8 44 - 23 0 0 -39 21 42 19 53 59 55 284 -7 -39 53 14 -38 50 13 -40 37 30 -38 6 14 - 22 0 0 -39 18 50 19 54 2 54 283 -8 -39 50 23 -38 47 20 -40 34 40 -38 3 20 - 21 0 0 -39 15 34 19 54 4 53 282 -8 -39 47 9 -38 44 3 -40 31 27 -38 0 1 - 20 0 0 -39 11 55 19 54 6 53 281 -9 -39 43 30 -38 40 22 -40 27 51 -37 56 18 - 19 0 0 -39 7 51 19 54 9 52 280 -10 -39 39 28 -38 36 17 -40 23 51 -37 52 12 - 18 0 0 -39 3 24 19 54 11 51 279 -11 -39 35 3 -38 31 49 -40 19 27 -37 47 41 - 17 0 0 -38 58 33 19 54 13 50 278 -12 -39 30 13 -38 26 56 -40 14 40 -37 42 45 - 16 0 0 -38 53 18 19 54 16 49 277 -12 -39 25 0 -38 21 39 -40 9 29 -37 37 26 - 15 0 0 -38 47 38 19 54 18 49 276 -13 -39 19 23 -38 15 58 -40 3 55 -37 31 42 - 14 0 0 -38 41 35 19 54 20 48 276 -14 -39 13 21 -38 9 52 -39 57 57 -37 25 34 - 13 0 0 -38 35 8 19 54 22 47 275 -15 -39 6 56 -38 3 23 -39 51 35 -37 19 1 - 12 0 0 -38 28 16 19 54 24 46 274 -16 -39 0 7 -37 56 29 -39 44 49 -37 12 4 - 11 0 0 -38 21 0 19 54 27 46 273 -16 -38 52 54 -37 49 11 -39 37 39 -37 4 42 - 10 0 0 -38 13 20 19 54 29 45 272 -17 -38 45 16 -37 41 28 -39 30 5 -36 56 56 - 9 0 0 -38 5 16 19 54 31 44 272 -18 -38 37 15 -37 33 21 -39 22 7 -36 48 45 - 8 0 0 -37 56 47 19 54 33 43 271 -19 -38 28 49 -37 24 49 -39 13 45 -36 40 10 - 7 0 0 -37 47 54 19 54 35 42 270 -20 -38 19 58 -37 15 53 -39 4 59 -36 31 10 - 6 0 0 -37 38 36 19 54 37 42 269 -20 -38 10 43 -37 6 32 -38 55 48 -36 21 44 - 5 0 0 -37 28 54 19 54 39 41 269 -21 -38 1 4 -36 56 47 -38 46 14 -36 11 55 - 4 0 0 -37 18 46 19 54 41 40 268 -22 -37 51 0 -36 46 36 -38 36 14 -36 1 40 - 3 0 0 -37 8 15 19 54 43 39 267 -23 -37 40 32 -36 36 1 -38 25 51 -35 51 0 - 2 0 0 -36 57 18 19 54 45 38 266 -24 -37 29 39 -36 25 1 -38 15 2 -35 39 55 - 1 0 0 -36 45 56 19 54 47 38 266 -25 -37 18 21 -36 13 36 -38 3 49 -35 28 25 0 0 0 -36 34 10 19 54 49 37 265 -25 -37 6 38 -36 1 46 -37 52 12 -35 16 30 1 0 0 -36 21 59 19 54 51 36 264 -26 -36 54 30 -35 49 31 -37 40 10 -35 4 9 2 0 0 -36 9 22 19 54 53 35 264 -27 -36 41 58 -35 36 50 -37 27 42 -34 51 24 3 0 0 -35 56 20 19 54 54 34 263 -28 -36 29 0 -35 23 45 -37 14 50 -34 38 13 4 0 0 -35 42 54 19 54 56 33 262 -29 -36 15 37 -35 10 14 -37 1 33 -34 24 36 5 0 0 -35 29 2 19 54 58 33 262 -30 -36 1 50 -34 56 18 -36 47 51 -34 10 35 6 0 0 -35 14 45 19 55 0 32 261 -30 -35 47 37 -34 41 57 -36 33 44 -33 56 8 7 0 0 -35 0 2 19 55 1 31 260 -31 -35 32 58 -34 27 10 -36 19 12 -33 41 15 8 0 0 -34 44 55 19 55 3 30 260 -32 -35 17 55 -34 11 58 -36 4 15 -33 25 57 9 0 0 -34 29 21 19 55 5 29 259 -33 -35 2 26 -33 56 20 -35 48 52 -33 10 13 10 0 0 -34 13 23 19 55 6 28 258 -34 -34 46 32 -33 40 18 -35 33 5 -32 54 4 11 0 0 -33 56 59 19 55 8 27 258 -35 -34 30 13 -33 23 49 -35 16 52 -32 37 30 12 0 0 -33 40 10 19 55 9 27 257 -36 -34 13 29 -33 6 56 -35 0 14 -32 20 30 13 0 0 -33 22 56 19 55 11 26 257 -37 -33 56 19 -32 49 37 -34 43 10 -32 3 5 14 0 0 -33 5 16 19 55 12 25 256 -37 -33 38 43 -32 31 52 -34 25 42 -31 45 14 15 0 0 -32 47 11 19 55 13 24 255 -38 -33 20 43 -32 13 43 -34 7 48 -31 26 58 16 0 0 -32 28 40 19 55 15 23 255 -39 -33 2 17 -31 55 8 -33 49 29 -31 8 16 17 0 0 -32 9 45 19 55 16 22 254 -40 -32 43 27 -31 36 7 -33 30 44 -30 49 9 18 0 0 -31 50 24 19 55 17 21 254 -41 -32 24 11 -31 16 42 -33 11 35 -30 29 38 19 0 0 -31 30 38 19 55 19 20 253 -42 -32 4 30 -30 56 51 -32 52 1 -30 9 41 20 0 0 -31 10 28 19 55 20 19 253 -43 -31 44 24 -30 36 36 -32 32 2 -29 49 19 21 0 0 -30 49 52 19 55 21 18 252 -44 -31 23 53 -30 15 56 -32 11 37 -29 28 32 22 0 0 -30 28 52 19 55 22 18 252 -45 -31 2 57 -29 54 51 -31 50 49 -29 7 20 23 0 0 -30 7 27 19 55 23 17 251 -46 -30 41 37 -29 33 21 -31 29 35 -28 45 44 24 0 0 -29 45 37 19 55 24 16 251 -47 -30 19 52 -29 11 27 -31 7 57 -28 23 44 25 0 0 -29 23 24 19 55 25 15 250 -47 -29 57 43 -28 49 9 -30 45 55 -28 1 19 26 0 0 -29 0 46 19 55 26 14 250 -48 -29 35 10 -28 26 27 -30 23 28 -27 38 30 27 0 0 -28 37 45 19 55 27 13 249 -49 -29 12 14 -28 3 21 -30 0 38 -27 15 18 28 0 0 -28 14 20 19 55 27 12 249 -50 -28 48 53 -27 39 51 -29 37 24 -26 51 42 29 0 0 -27 50 31 19 55 28 11 248 -51 -28 25 9 -27 15 58 -29 13 46 -26 27 43 30 0 0 -27 26 20 19 55 29 10 248 -52 -28 1 2 -26 51 42 -28 49 45 -26 3 21 31 0 0 -27 1 46 19 55 29 9 247 -53 -27 36 32 -26 27 4 -28 25 22 -25 38 36 32 0 0 -26 36 49 19 55 30 8 247 -54 -27 11 40 -26 2 3 -28 0 35 -25 13 30 33 0 0 -26 11 30 19 55 30 7 246 -55 -26 46 25 -25 36 40 -27 35 27 -24 48 1 34 0 0 -25 45 50 19 55 31 6 246 -56 -26 20 49 -25 10 55 -27 9 56 -24 22 11 35 0 0 -25 19 48 19 55 31 5 245 -57 -25 54 51 -24 44 49 -26 44 4 -23 55 59 36 0 0 -24 53 25 19 55 31 4 245 -58 -25 28 32 -24 18 23 -26 17 51 -23 29 27 37 0 0 -24 26 42 19 55 32 3 245 -59 -25 1 53 -23 51 36 -25 51 16 -23 2 35 38 0 0 -23 59 38 19 55 32 2 244 -60 -24 34 53 -23 24 29 -25 24 22 -22 35 23 39 0 0 -23 32 16 19 55 32 1 244 -61 -24 7 34 -22 57 2 -24 57 8 -22 7 52 Uncertainty in time = +/- 3 secs Prediction of 2012 Jul 21.0 Data for the target star ------------------------ * name: HIP 75934 * constellation : Libra * J2000 position with proper motion to date of event [h,m,s ; °,',"] RA: 15 30 34.4933 DE: -24 17 58.524 * position source: mpos:UCAC2 pm:UCAC2 plx:HIP2 * standard error: RA,DE ["]: ( .028, .034 ) * V mag [mag]: 10.1 * B mag [mag]: 11.0 * Apparent position with proper motion RA(deg): 232.8338093079 DE(deg): -24.3423431303 * Equation of equinoxes (radians) : 0.000067230049131 * Diameter [mas]: 0 * remarks: Data for the minor planet ------------------------- * general information: (number) name: (127) Johanna approx. diameter [km]: 114 approx. diameter ["]: .050 distance from Earth [AU]: 3.17100 * orbital information: orbit source: Preston date of fit: 2012 Jul 21 source of used astrometry: FASTT TMO MPC (via Astdys) number of used observations: 956 number of rejected observations: 98 time covered by the observations: 1917 Oct 03 - 2012 Jun 27 1 sigma uncertainty ellipse (major, minor, PA): 0.011, 0.007, 112° remarks: * orbital elements for (127) Johanna : Mean anomaly = 122.91496468 deg Arg. of pericenter = 94.76608088 deg Long. of node = 31.21426359 deg Inclination = 8.24067799 deg Eccentricity = 0.06554491 Semimajor axis = 2.75614973 AU Perihelion dist = 2.57549813 AU Mag: H = 8.49, G = 0.15 Epoch of elements : MJD 56185.82800000 TDT (2012 Sep 15.828) ------ occelmnt file for Occult BEGIN ----------------------------------- 2012 Sep 15 127 Johanna 19h 52.1m UT 10.1 15 30 34.493-24 17 58.52HIP 75934 11.0 14.0 114 3.8 3.171 3.372 -11.42 -60.5629 -24.297 -119.29 2.63 19.8686 -0.04379 -0.19415 16.62014 -4.11950 0.00491 -0.00146 2000 121.6596022012 910.00000 94.766081 31.214264 8.2406780.06554491 2.7561497 2.5754981 8.3 5.00.15 RATE 2.1540200 0.000000 0.000000 0.000000 0.0000000 0.0000000 0.0000000 Meas 0.035 0.030 1 1.70 0.035 0 0 3-4 056129.0020120915__75934 ------ occelmnt file for Occult END ----------------------------------- ============================================ Calculator (s): Steve Preston Date of update: 2012 Jul 22, 03:54 UT Steve Preston 7640 NE 32nd St Medina, WA 98039 425-688-9965 mailto: stevepr@acm.org